Gymnasium springboard



March 18, 1952 B. c. SIDLINGER 2,590,049

GYMNASIUM SPRINGBOARD Filed Feb. 7. 1949 2 SHEETSSHEET 1 FIGJ.

FIG. 2.

IN V EN TOR.

BRUCE C. SIDLI NGER BY FISHER AND CHRISTEN HTTORNE YS.

March 1952 B. c. SIDLINGER GYMNASIUM SPRINGBOARD 2 SHEETS--SHEET 2 Filed Feb. 7. 1949 INVENTOR. BRUCE .c. SIDLINGER FISHER AND CHRISTEN H T TORNEYS.

Patented Mar. 18, 1952 UNITED STATES PATENT OFFICE GYMNASIUM SPRINGBOARD Bruce C. Sidlinger, Cedar Rapids, Iowa Application February 7, 1949, Serial No. 74,939

Claims.

This invention relates generally to gymnastic equipment of the trampolin type tumbling mat and more particularly to a collapsible springboard structure.

Gymnasium springboards available in the past have always been heavy and bulky and not suffi;- ciently springy to be popular. Professional acrobats have need of a small, collapsible and sturdy device to assist them in bounding onto larger equipment or to the backs of circus animals.

It is a general object of my invention to provide a gymnasium springboard structure which is light weight but strong and achieves resilience far superior to the conventional type device for this purpose.

It is a further object of my invention to provide a gymnasium springboard which will fold up compactly for storage or transporting from place to place.

It is still another object of my invention to provide a gymnasium springboard which is easily set up and is self locking, requiring no bolts or special devices which must be adjusted to secure the device in its usable condition.

It is still another object of my invention to provide a gymnasium springboard which may be easily collapsed by applying pressure with the users'foot in the proper place.

It is still another object of my invention to provide a gymnasium springboard which may be inclined and means thereon for varying the angle of inclination.

It is still another object of my invention to provide a gymnasium springboard which is of simple design and constructed of common materials so as to be relatively inexpensive to produce and easy to maintain.

' It is still another object of my invention to provide a gymnasium springboard which is small in size, the take-off surface and its supporting frame being reduced to a minimum compatible with safety.

These and other objects of the invention will be readily understood by reference to the accompanying drawings and following specification, wherein is disclosed a preferred exemplary embodiment of the invention.

. In general, the present invention is directed to a foldable gymnasium springboard comprising a two-part frame, means, including hinges, for pivoting the two parts of the frame together and locking them in unfolded position, a resilient take-off surface carried by said two-part frame, a pair of short legs carried by one part of said frame, a pair of longer legs pivoted to the other part of said frame, and flexible tension means interconnecting said pairs of legs. In the preferred embodiment shown, there is included a two-part frame, means forming a toggle joint hingedly connecting said two-part frame, for holding the two parts of the frame in the same plane when extended, the pivot of said toggle joint being below the dead center of said frame when extended, a pair of short legs secured to one of said frame members, a pair of longer legs variable in length and pivoted to the other of said frame members, flexible tension members interconnecting said pairs of legs, said pairs of legs converging upwardly when the springboard is unfolded to position the unfolded frame, at an incline, whereby a downward pressure on the uppermost edge ofv the upper frame will cause the toggle to break upwardly for folding.

In the accompanying drawings:

Fig. 1 is a plan view of a gymnasium springboard constructed in accordance with a preferred embodiment of my invention;

Fig. 2 is a side elevation view of the device illustrated in Fig. 1, broken away in part to show how the stretched, take-off surface material exerts a force to hold the device locked in normal operating position;

Fig. 3 is a side elevation view of the device illustrated in Fig. 1 and Fig. 2 as it appears when it is just starting to fold and showing how the tension of the rubber shock cord which supports the take-off surface material assists in folding the device after the line of force is below the frame joint, and

Fig. 4 is a side elevation view of the device illustrated in Figs. 1, 2 and 3 as it appears in the completely folded position.

Referring now to the drawings in which like refernce numerals refer to like parts; a take-off surface in, preferably woven of parachute strap webbing, is fitted on its edges with a continuous rope ll inserted in the looped ends of the said webbing. Take-off surface i0 is resiliently supported byga continuous length of rubber shock cord l2 woven between rope II and heavy wire loop [3. Wire loops I3 are fastened, preferably by welding, to frame M which is of tubular steel or the like. Frame [4 is formed of two U-shaped parts Ma and Mb adapted for folding by hinges l5 at points I5P and is slightly arched outwardly at each side for increased strength.

One pair of tubular supporting legs [6 are rigidly connected to the underside of the frame part Mb, preferably by welding, and preferably reinforced, as by frame I 1. Another pair of tubular legs l8 are joined, preferably by welding, to a sleeve IS. The sleeve I9 is adapted to be pivotally mounted over frame part Ma. Legs 18 are provided with telescopic extension members which are locked in any extended position by lock screws 2|. The lower ends of legs 16 and extension members 20 are preferably provided with friction foot pads 22, such as rubber brakepedal type pads.

The legs, 16 and I8 are joined adjacent their base portions by a pair of flexible, non-resilient tension members 23, preferably in the form of chains, as shown. The chain members 23 serve to limit the outward movement of the legs 18 by rotation of the sleeve 19 around the frame portion I 4a. Said chain members 23 also provide proper resistance against outward relative move ment of the legs [6 and I8 when collapsing force, shown by arrow 24 in Fig. 3, is applied. Chain members 23 are also used for securing the apparatus in its compactly folded and locked condi tion as shown in Fig. 4. In this position, the chain members 23 may be held in tension by positioning the chains 23 in the angular hook portion 25 defined by the hinge l5 and abutment ends of the frame members Ma and Mb.

In use, the downward loading on take-off surface H) is resisted by the links or chain members 23. This resistance acts in conjunction with the slope of legs I5 and I8 to exert a force which keeps the frame locked in the desired set-up position. This effect is further influenced toward the same end by offsetting pivot points I 5? below the dead center line CL of the tubular frame M.

The pivots IESP of the hinges are positioned below the planar or lateral dead center line CL of the two-part frame members when fully extended, as shown in Fig. 2. This relative arrangement of the pivots l5P below 'the dead center line CL, and therefore below the longitudinal axis LA of the sleeve [9 which is shown in the same plane as the center line CL, enables the collapsing movement to-take place by application of the downward force shown by arrow 24.

Thus, the present structure may be-readily collapsed by the user by applying downward pressure, as by means of the users foot, on the sleeve I9, as indicated by the arrow 24. This movement causes the frame to break upwardly at the hinge points 15, the legs l6 and I 8 being held against outward relative movement at the points where they are joined by the tension members 23. As soon as the frame has been broken upwardly at the hinge points, the force of the resilient tensioned shock cord is suflicient to complete the collapsing movement of the structure .as shown in Figs. 3 and 4. It should be further noted that hinges at points l5 are preferably not equidistant between the frame ends thereby allowing more compact folding, as shown in Fig.4.

While I have shown a preferred embodiment of my invention, it will be understood that various modifications may be made therein without departing from the spirit and scope of the invention and I intend to include all such modifications as covered by the following claims.

I claim:

1. A foldablegymnasium springboard, comprising in combination, a two-part, generally rectangular frame, including two generally U-shaped members, the arms of which are respectively abutted at their ends, means including a hinge positioned below the level of the abutting ends of the said arms for pivotably joining said U-shaped members whereby said U-shaped members lie in the same plane when the ends of said arms are in abutting relationship and the pivoting motion from the single plane is only upward, a flexible take-off surface resiliently supported within said frame, a fixed pair of legs attached to and supporting one of said frame members, a pair of legs pivotably attached to the base of the other of said u-shaped members and extending downwardly and outwardly therefrom and defining an :angle greater than with said frame, and flexible tension means interconnecting said pairs of legs.

2. A foldable gymnasium springboard, comprising in combination, a two-part, generally rectangular frame, including two generally .U -shaped members, the arms of which are respectively abutted at their ends, means including a hinge positioned below the level of the abutting ends of said arms for pivotably joining said U-shaped members whereby said U-shaped members lie in the same plane when the ends of said arms are in abutting relationship and the pivoting motion from the single plane m only upward, a flexible take-off surface resiliently supported within said frame, a fixed pair of short legs attached to and supporting one of said frame members, a pair of relatively longer legs pivotably attached to the base of the other of said U-shaped members and extending downwardly and outwardly therefrom and defining an angle greater than 90 withsaid frame, and flexible tension means interconnecting saidpairs of legs.

3. The device as set forth in claim 2 wherein said pivoted longer legs are provided with telescopic means for varying the length thereof.

4. The device as set forth in claim 2 wherein said pair of short'fixed legs are integrally secured to the frame member and including a pair of braces integrally secured respectively to both the same frame member and said fixed legs to form a rigid triangular support unit.

5. The device as set forth in claim 2 including asleeve fixedly carrying said pivoted longer legs, said sleeve being rotatably mounted on the base of one of said U-shaped members whereby both of said legs pivot in unison.

BRUCE C. SIDLINGER.

REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,434,100 Creasy Oct. 31, 1922 2,370,990 Nissen Mar. '6, 1945 2,468,253 Deanv A'pr. 26, 1949 FOREIGN PATENTS Number Country Date 385,047 Great Britain 1932 

